Features: 1. 100% brand new and high quality. 2. Appearance of light and novel, easy to carry, easy to operate 3. Menu operation interface, battery power real time. 4. Sound, light and vibration alarm 5. There is a kind of essential safety instrument which can continuously detect the oxygen concentration in the working environment 6. Widely used in metallurgy,power plant, chemical, mine, tunnel, underground pipelines and other places, effective prevention of hypoxia and oxygen poisoning. Specification: Condition: 100% Brand New Model: 803 Sensor: Electrochemical Principle Detection Gas: Oxygen O2 Temperature Measurement: Ambient Temperature Display Unit: O2: %VOL Temperature: ℃ / ℉ Range: O2: 0~25%VOL Temperature: -15~50℃ Resolution: O2: 0.1% VOL Temperature: 0.1 ℃ -0.1 ℉ Response Time: T90 Less Than 15s Alarm: sound and light alarm Alarm Point: low alarm point 19.5%VOL High alarm point 23.5%VOL Battery Type: 3 * AAA/7 alkaline batteries(not included) Operating Temperature: -10~+50℃ Operation Humidity: 15%-95%RH(no condensation) Weight: Approx. 176g / 6.2oz Package List: 1 * Oxygen Gas Detector Note: 1. Improper operation or inappropriate use of the environment may weaken the operating performance of the instrument. For the safest and most effective use of the instrument, please read the following correct operating procedures and safety 2. Please read the operation manual carefully before any operation is performed. 3. The window and filter membrane of the sensor must be kept clean. If the sensor window is blocked or filtered by the water film, it may result in a reading below the actual gas concentration 4. Tho replacement of batteries, maintenance parts and other operations can only be carried out in a safe environment. 5. In order to ensure the safety and the proper use of the instrument, the operation and maintenance of the instrument can only be carried out by qualified personnel. 6. Every day before use please check the accuracy of the instrument in the fresh air, ensure that the measurement error is within the allowable range. If it exceeds the allowable error range, the instrument must be calibrated. 7. Keep the alarm through the mouth dean, no foreign objects clogging, otherwise it will lead to not hear the alarm or alarm information identification 8. Removing and replacing the battery must be performed in a known, no hazardous environment.